Struct OccupiedEntry

pub struct OccupiedEntry<'a, T, S, A: Allocator = Global> { /* private fields */ }

A view into an occupied entry in a HashSet. It is part of the Entry enum.

Examples

use hashbrown::hash_set::{Entry, HashSet, OccupiedEntry};

let mut set = HashSet::new();
set.extend(["a", "b", "c"]);

let _entry_o: OccupiedEntry<_, _> = set.entry("a").insert();
assert_eq!(set.len(), 3);

// Existing key
match set.entry("a") {
    Entry::Vacant(_) => unreachable!(),
    Entry::Occupied(view) => {
        assert_eq!(view.get(), &"a");
    }
}

assert_eq!(set.len(), 3);

// Existing key (take)
match set.entry("c") {
    Entry::Vacant(_) => unreachable!(),
    Entry::Occupied(view) => {
        assert_eq!(view.remove(), "c");
    }
}
assert_eq!(set.get(&"c"), None);
assert_eq!(set.len(), 2);

Implementations

impl<T, S, A: Allocator> OccupiedEntry<'_, T, S, A>

pub fn get(&self) -> &T

Gets a reference to the value in the entry.

Examples

use hashbrown::hash_set::{Entry, HashSet};

let mut set: HashSet<&str> = HashSet::new();
set.entry("poneyland").or_insert();

match set.entry("poneyland") {
    Entry::Vacant(_) => panic!(),
    Entry::Occupied(entry) => assert_eq!(entry.get(), &"poneyland"),
}

pub fn remove(self) -> T

Takes the value out of the entry, and returns it. Keeps the allocated memory for reuse.

Examples

use hashbrown::HashSet;
use hashbrown::hash_set::Entry;

let mut set: HashSet<&str> = HashSet::new();
// The set is empty
assert!(set.is_empty() && set.capacity() == 0);

set.entry("poneyland").or_insert();
let capacity_before_remove = set.capacity();

if let Entry::Occupied(o) = set.entry("poneyland") {
    assert_eq!(o.remove(), "poneyland");
}

assert_eq!(set.contains("poneyland"), false);
// Now set hold none elements but capacity is equal to the old one
assert!(set.len() == 0 && set.capacity() == capacity_before_remove);

Trait Implementations

impl<T: Debug, S, A: Allocator> Debug for OccupiedEntry<'_, T, S, A>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 24 bytes